The key thing with a Switch Axe is the phial, as well as the during attacks transitions between modes. Ideally start off with either power phials or exhaust phials (focus on the head if this is the phial you use) There is no real best switch axe, focus on attack and sharpness rather than element.Bone would be best to start off with.

-------------------Monster Hunter Veteran. I hope you all have a nice day